If you have a multimeter check the heating element and thermostat,
they maybe two stats on your machine so check the above for open circuits,
the build up of grease may suggest a heating issue.
if the machine was running at the correct temperature then maybe the grease build up should not be there?,
just thought I would mention that,
what harm can metering the heating system do,
just a suggestion,
good luck....
paul, March 2012